Instrument Hook-up Drawing Hook-up drawing is a detailed drawing showing typical installation of instrument in a correct manner so that instrument operates properly (gives accurate indication and  prevent any issued which could potentially  affect the measurement such as liquid trap in gas impulse line). Hook-up drawing indicates tubing slopes, position of instrument in reference to process tapping point, scope break between instrument vs piping. Hook-up drawing also gives information the requirement of bulk material for each installation. It also details its specification (size, type and material) and the quantity. There are two types of hook-up drawing: Process Hook-Up This hook-up drawing contains typical installations for instrument which connects to the process Pneumatic Hook-Up This hook-up drawing contains typical installations for instrument which requires instrument air such as control valve, actuated valve Reference drawing: P&ID, Installation Detail Spec